What is the minimum height requirement for waterproof material on shower walls and built-in tubs?

The minimum height requirement for waterproof material on shower walls and built-in tubs is set at 6 feet. This standard is established to ensure that the areas most likely to encounter water spray and moisture are adequately protected, preventing water damage and reducing the risk of mold growth. The height of 6 feet ensures that at least the full height of the typical user is accommodated, which is essential for effective water containment during showering or bathing. This requirement promotes safety and durability in bathroom construction, aligning with best practices in plumbing and building codes.